Japanese healthcare company Daiichi Sankyo Co Ltd (TYO:4568) and British-Swedish biopharmaceutical company AstraZeneca plc (STO:AZN) (LON:AZN) (Nasdaq:AZN) said on Monday that their therapy DATROWAY (datopotamab deruxtecan) achieved statistically significant and clinically meaningful improvements in overall survival and progression-free survival in the phase 3 TROPION-Breast02 trial.

The results mark DATROWAY as the first and only therapy to significantly improve overall survival compared with chemotherapy for patients with metastatic triple negative breast cancer (TNBC) who are ineligible for immunotherapy.

DATROWAY, a TROP2-directed DXd antibody drug conjugate discovered by Daiichi Sankyo, is being jointly developed and commercialised by the two companies. The safety profile observed in the trial was consistent with previous studies of DATROWAY in breast cancer.

Approximately 70% of patients with metastatic TNBC are not candidates for immunotherapy, making chemotherapy the current first-line standard of care. The companies plan to present full data from TROPION-Breast02 at an upcoming medical meeting and initiate global regulatory submissions.

Daiichi Sankyo and AstraZeneca are also studying DATROWAY in three additional phase 3 trials -- TROPION-Breast03, -Breast04, and -Breast05 -- across multiple treatment settings and stages of TNBC.